1. Field of the Invention
The present invention relates to a planar light source device and a display apparatus having the planar light source device, more particularly, to the planar light source device capable of making uniform luminance and the display apparatus having the planar light source device.
2. Description of the Related Art
A display apparatus, generally, displays images using data that is processed by an information processing device. The display apparatus is classified into a cathode ray tube (CRT), a plasma display panel (PDP), a liquid crystal display (LCD) apparatus, an organic electro luminescent display (OELD) apparatus, etc. The LCD apparatus displays the image using liquid crystal.
In the LCD apparatus, the arrangement of the liquid crystal varies in accordance with an electric field applied thereto, and thus light transmittance may be changed. For example, the LCD apparatus displays the images using electric and optical characteristics of the liquid crystal. The LCD apparatus is slimmer and lighter than the CRT. Therefore, it is widely used in various electronic apparatuses, such as a portable computer, a communication equipment, a television receiver set, an aerospace device, etc.
A conventional LCD apparatus includes a liquid crystal controlling part that controls the liquid crystal, and a light supplying part that supplies the liquid crystal controlling part with light.
The liquid crystal controlling part includes a pixel electrode formed on a first substrate, a common electrode formed on a second substrate and the liquid crystal disposed between the pixel electrode and the common electrode. The liquid crystal controlling part includes a plurality of the pixel electrodes. The number of the pixel electrodes corresponds to a resolution of the LCD apparatus. The common electrode is disposed at a position corresponding to the pixel electrodes. A plurality of thin film transistors (TFT) are electrically connected to the pixel electrodes to apply pixel voltages to the pixel electrodes, respectively. The pixel voltages may be different from one another. A reference voltage is applied to the common electrode. The pixel electrode and the common electrode of the LCD apparatus include a transparent conductive material.
The light supplying part supplies the liquid crystal controlling part with the light. The light successively passes through the pixel electrode, the liquid crystal and the common electrode, so that the liquid crystal controlling part displays the image. Image display quality of the LCD apparatus improves in proportion to uniformity of the luminance of the light.
The light supplying part includes a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED). The CCFL has various characteristics, such as high luminance, high efficiency, long lifetime, thin thickness, light weight and low cost and so on. The CCFL and the LCD, however, have non-uniform luminance. Therefore, the light supplying part having the CCFL includes optical members, such as a light guide panel (LGP), a light diffusion member, a prism sheet, etc. to improve the uniformity of the light. When the light supplying part includes the optical members, the size and weight of the LCD apparatus increase.
Recently, a planar light source device has been developed to solve these problems. The planar light source device includes a light source body that forms a discharge space, and a plurality of partition members that divide the discharge space into a plurality of discharge regions. The planar light source device also includes electrodes that are formed the side of the light source body. Plasma in the discharge space is generated by a discharge voltage applied to the electrodes.
However, the conventional planar light source device has a problem that electric charges generated by the discharge voltage are concentrated on the edges of the partition members, thereby the uniformity of luminance becomes poor.